Method and apparatus for balancing crank shafts and the like



METHOD AND APPARATUS FOR BALANCiNG CRANK SHAFTS AND THE LIKE.

I APPLICATION FILED FEB. 14.| 1921.

1,42 6% PatentedSept. 12, 19225 Patented Sept. 12, 1922.

to sure r rs h s 1 we 9- i er i: gj w at it it. o bra "M w. lu" o CARL L. wILBnn, OF";DETROIT, urcnrcannssrenoa TO THE .snrrnnson FORGE rnonuc'rs 00., or nn'rnorr. MICHIGAN, A eonrona'rron or MICHIGAN.

METHOD AND APPARATUS FOR BALANCING C RANK SHAFTS AND THE LIKE.

Application filed February 14, 1921. Serial No. 444,926.

To all whom it may concern:

Be it known that I, CARL L. hnnnn, a citizen of the United States, of America, residing at Detroit, in the county ofVV-ayne and Stateof Michigan, have invented certain new and useful. Improvements in Methods and Apparatus for Balancing Crank Shafts and the like, of which the following is a specification, reference being'had therein to the accompanying drawings.

The invention relates to the method and apparatus for balancing crank shafts and has for its primary object the obtaining of a preliminary balanceprior to any machining operation, which lessens the work and amount of material which must be removed in obtaining thelinal balance. In the present state of the art it is usual to first form center bearings in the opposite ends of the shaft, Which are concentric with the end bearing portions ofsaid shaft. It frequently happens that in the forging these end bearing portions are not concentric with the axis of balance of the forging and therefore after the machining of the shaft, the structure is far out of balance. With my improved method the center bearings are formed concentric to the axis of balance in the forging instead of being concentric with the bearing portions thereof, with. the result that less work must be performed in the subsequent balancing operation.

To accomplish this purpose I preferably employ centering jigs which are attachable to the opposite end portions of the shaft and are adjustable into concentric relation with the balance axis of the shaft, said jigs also having true cylindrical surfaces for use in obtaining the initial balance. When said jigs are secured and properly positioned, center bearing forming tools are engaged therewith and center bearings formed in the opposite ends of the shaft. The jigs are then removed and the machining of the shaft is proceeded with, after which it may be balanced with less difliculty than by methods heretofore used.

In detail and as shown in the drawings:

Figure 1 is a sectional elevation showing a crank shaft with the centering jigs applied thereto illustrating the manner of obtaining the initial balance;

Figure 2 is a sectional side elevation and Figure 3 an end elevation of one of the centering jigs; I 7

Figures 4: and 5 are similar views of the other of the centering jigs. I

Each of these centering jigs is formed with a portion A having cylindrical outer surface and a concentric bore B of a diameter to receive and form aguide fora center bearing forming tool such as C. The igs are further provided with means for adjustablv engaging the same with .the ends of the shaft,-preferably sleeve portions D, having set-screws 1*} extending radially therethrougl'i and equally. spaced about the periphery. here. the shaft is formed witha flanged end such as F, the sleeve portion D is enlarged in diameter to surround the pe riphery of this flange, as shown in Figures 2 and 3. i I I To obtain the initial balance, the are secured to the opposite endsof the shaft by the clamping action of the set-screws E and the shaft is then placed with the cylindrical bearing surfaces of the jigs resting upon horizontal knife-edge bearings G. If the shaft is not in balance, the set-screws E are adjusted and this operation is repeated until the structure is in substantial balance. The

serted in the guide bores B and center bearings are formed thereby in the ends of the shaft. The jigs are then removed and the machining of the shaft is proceeded with, the center bearings being used in the usual. way. The machined shaft is finally rebalanced in the usual manner.

My improved method not only simplifies the operation of obtaining the final balance, but also lessens the amount of surplus stock that must be provided in the original forging in order to insure the cleaning up of all portions of the shaft when machined.

What I claim as my invention is:

1. The method of balancing crank shafts and the like, comprising the forming of center bearings in the opposite ends of said shaft concentric to the axis of balance in the rough forging, finishing the forging members to arrange said true cylindrical surfaces concentric with the axis of balance in the rough forging and forming in the ends of the shaftcenter bearings concentric with said axis.

3. The method of balancing crank shafts and the like, comprising applying to the opposite ends of the shaft members having true cylindrical portions and sleeve portions for surrounding said shaft and spaced therefrom, adjusting said members radially to arrange the cylindrical portions thereof concentric with the axis of balance in the rough forging, forming center hearings in the ends of the shaft concentric with said cylindrical portions and removing said members and finishing the forging.

e. A device for balancin crank shafts and the like, comprising a member having a true cylindrical surface, means for engaging said member with the ends of the shaft and adjusting the same radially into concentric relation to the axis of balance in the rough forging, and a center bearing formingtool engageable with said member concentric to the cylindrical surface thereof for forming a center bearing .in the end of the shaft.

5. A device for centering crank shafts and the like, comprising a member having an outer cylindrical portion and a sleeve portion for surrounding the end of they shaft, said screws passing radially through said sleeve portion and engageable with a shaft to adjust said cylindrical surface concentric with the axis of balance, said. cylindrical surface forming a means for obtaining the balance, and center-forming means engageable with said member concentric to the cylindrical surface thereof for forming the bearing in the end of the shaft.

6. A device for centering crank shafts and the like, a member having a cylindrical outer surface, a bore concentric there with and a'sleeve portion for surrounding the end portion of the shaft, said screws spaced about said sleeve portion and extending radially therethrough into engage ment with the shaft, and a center bearii'ig forming tool engageable with said bore to be guided thereby in forming a center bearing in the end of the shaft.

L. A device for centering crank shafts HlCl the like, the combination of a. pair of centering jigs, each jig having a true outer cylindrical portion and a bore concentric to said cylindrical portion, sleeve portions extending inward from said to surround the end portions of the shaft, one of said sleeves being enlarged to receive the Hanged end. of the shaft, said screws arranged around said sleeve and extending radially therethrough into engagement with 'the pe riphery of said shaft and flange, and center bearing forming tools engageable with said bores and guided thereby.

in testimony whereof ll aiiix my signature.

" lARL L. W lliliihll't. 

